Kyocera Mita DC-1560, Service Manual

Page: 54 / 289

1AF
1-3-19
Exposure control for auto exposure mode
In auto exposure mode, the halogen lamp lights at the intensity set for mode 1 in simulation
22 to perform prescan. The exposure level to copy that particular original is determined by
using the value read in by the AE sensor.
100 mm
Original leading edge
AE detection (prescan)
Exposure
Original leading edge
148 mm
Original
Scanner
movement
Detection width
Figure 1-3-15 AE sensor detection width
Figure 1-3-16 Exposure control for auto exposure mode
The halogen lamp voltage is controlled so that the lamp lights at the intensity for manual-
mode Exp. 4 when the AE sensor read-in value is the NTC level set in mode 2 by simulation
22, and at the intensity for manual-mode Exp. 7-1 when the read-in value is the NPTC level
set in mode 3.
In auto exposure mode, the drum potential is decreased by 170 V from the normal level and
the halogen lamp voltage is increased when the AE sensor read-in value is below the setting
for mode 3 in simulation 22. When the AE sensor read-in value falls in the range between
the mode 3 and mode 2 settings by simulation 22, the halogen lamp voltage is controlled
based on the gradient determined by the values set by simulation 24. For read-in values
above the mode 2 setting of simulation 22, the halogen lamp voltage is kept at a constant
level so that the lamp lights at the intensity for manual-mode Exp. 4.
Halogen lamp voltage
Manual-mode Exp. 7-1
Drum potential 850 V DC
Drum potential 680 V DC
Manual-mode Exp. 4
Mode 3, sim. 22
(NPTC level) Mode 2, sim. 22
(NTC level)
AE sensor read-in value
0